Automatic valve for independent-rotation drills



W A. SMITH. AUTOMATIC VALVE FOR INDEPENDENT ROTATION DRILLS.

APPLICATION FILED MAY II, I918.

Patented, Mar. 29, 1921.

mm m Q Q g INVENTOR.

B I, /v

/ ATTORNEYS.

STATES earner "WILLIAIE A. SMITH, F EASTON, EENNSYLVANIA, ASSIGNOR TOINGERSOLL-EAND COIMPANY, OF JERSEY CITY, NEVT JERSEY, A CORPORATION OFNEW JERSEY.

AUTOMATIC VALVE FOB INDEPENDENT-ROTATION DRILLS.

Application filed May 11, 1918.

To all whom it may concern:

Be it known that 1, WILLIAM A. SMITH, a citizen of the United States,residing at Easton, in the county of Northampton and State ofPennsylvania, have invented a certain new and useful Improvement inAutomatic Valves for independent-Rotation Drills, of which the followingis a specification.

This invention relates to fluid operated percussive tools and inparticular to a fluid operated percussive drill having a fluid operatedmotor for rotating the drill steel or bit.

The objects of the present invention are to provide a fluid operatedtool of the above type with means to automatically control and regulatethe amount of fluid supplied to the drill bit rotating motor which willpermit a relatively small amount of fluid to pass from the main supplychest of the tool to the rotating motor when the drill is operating idlyand will permit a greatly increased amount of fluid to pass to the motorwhen the drill is operating under working conditions, and permit aproportionate amount of fluid to pass when the motor is operating undervarious conditions of load and speed. Furthermore, the means employedserve to prevent a waste of fluid when the drill is operating idly asfor instance when the drill is flrst started or while the drill is beingadvanced to the work or withdrawn therefrom, the means provided forautomatically controlling the supply of fluid to the rotating motorbeing independent of the means for supplying motive fluid to thepercussive element.

With these and other objects in view the present invention consists inthe features of construction and operation set forth in the followingspecification and illustrated in the accompanying drawings forming apart hereof, in which:

Figure 1 shows a longitudinal view of a percussive tool containing thepresent invention;

Fig. 2, a sectional view of the controlling valve for the rotatingmotor.

Fig. 3, a longitudinal view of the forward portion of a percussive drillshown in section; and

Fig. 1, a sectional view taken on the line 4-4 of Fig. 3.

Referring more particularly to the draw- Specification of LettersPatent.

Patented Mar. ea, rear.

Serial No. 233,978.

ings, 1 refers to the cylinder of a percussive tool provided with thepresent invention. Within the cylinder 1 reciprocates the piston 2 whichat the forward end of its stroke strikes the drill bit 3 retained inplace within a chuck 4 in the forward end of the cylinder 1. A rotatingmotor 5 which comprises a pair of spur gears operates through gears 6 agear .7 provided on the chuck 4 to rotate the chuck 4 simultaneouslywith the reciprocations of the piston 2.

Fluid for operating the piston and rotating motor is supplied from asuitable source (not shown) the conduit or passage for supplying thefluid to the rotating motor 5 being shown at 8. Within this conduit 8 islocated the valve forming the subject matter of the present invention.This valve comprises a sleeve 9 secured transversely in the cylinder 1by means .of a threaded portion 10 and within the sleeve 9 is a hole 11extending substantially throughout its length in which fits a valve 12.In the position of the valve as shown in Fig. 2 fluid passing throughconduit 8 is allowed to leak past the outer head 13 of the valve .12into a branch conduit 1 1 to the conduit 15 leading directly to therotating motor 5. For this purpose the valve sleeve 9 is provided withslotted or. cut out portions 16. to permit the fluid mitted to passthrough the sleeve 9 and past the valve 12 at all times, in order toinsure that the pressure ahead of the motor will build up and beavailable to open the valve wider if the motor is stalled or retarded.The valve 12 is held in the position shown by means of a light spring 17contained within the sleeve 9 and pressing against the outer head 13 ofthe valve 12. An additional inner valve head 18 is provided whichbalances the valve against endwise movement due to fluid pressure andfor convenience the valve has short projections 19 at either end one ofwhich serves to prevent the valve 12 from completely closing OK thepassage through the valve and the other serves to make the valvesymmetrical and reversible.

The valve 12 when there is no pressure in p 15 to the motor 5.

creased flow of fluid through conduit 15to rotate motor 5, which amountis dependent upon the pressure against thedrill bit and the speed ofrotation of the drill bit.

The branch conduit 14 is extended to intercept and join the lower end ofthe sleeve 9 and valve 12 so that the pressure on the farther side ofthe valve 12 from the fluid supply will be always acting on the'end ofthe valve to press it upwardly and enlarge the opening through the valve12 from conduit 8 to 15. The spring 17 is, however, just suflicientlystrong to hold the valve 12 in the position shown when the pressure inthe conduit 14 is very low and when pressure in conduit 14 increasesabove a given pressure the fluid pressure acting against the piston head18 or in other words the back pressure in conduit 15'unbalances thevalve 12 and forces it to move upwardly and open more widely the passagefrom conduit 8 to 14'.

In operation, when the drill is operating idlyithe motor 5 takes butvery little fluid to operate it and after the motor comes iup to itsmaximum speed the motor will operate on a pressure insufficient to openthe valve; that is, the pressure within the conduit 14 will beinsuflicient to counteract the pressure .of the spring 17 7 As soon,however,.as'resistance is encountered in rotating the :drill" bit 3,pressure increases in the conduits 14 7V and 15 and a back pressure isexerted against the valve dependent upon the speed-of motor 5 andpressure on the drill bit 3 so that the pressure on the lower end of theinner head 18 is increased suflicientlyto force the valve to partiallyopen and allow additional pressure to reach and operate the motor 5.When the resistance to the rotation of the drill bit 3 is withdrawn aswhen the drill is I being removed from the hole the back pressureagainst the valve 12 within'conduits 14 and'15 drops to a pointsufiicient-to permit 1 the spring 17 to expand and partially close thevalve again so that the rotation is continued by a very smallexpenditure of fluid.

It is to be understood that the present showing and description discloseonly one SPQClilC embodiment of the present invention,

and that other forms and modifications are included within the spiritand scope thereof,

' as expressed in the appended claim;

7 a stemand inner and outer heads, the outer head controlling the portin the sleeve leading to the motor, and the inner head closing saidsleeve and having a projection adapted to bear 'on the valve chest andnormally maintain the valve open so as to permit a small quantity offluid to flow past-the outer head to the motor and keep the motorrunning under light load, and insure that the pressure ahead of themotor will build up and beavailable to open the valve wider if the motoris stalled or retarded.

In testimony whereof, I havehereunto-set my hand. r

, wiLLii M'A. sMrrH Witness WM. C. MORRIS.-

